If you’re like me, the iPad has changed how you look at computers in just a matter of weeks. The possibilities for this device seem endless. It’s natural at this point to start thinking about the future, and to do that thinking in terms of the past.

As an example, we’ve been getting plenty of feature requests for Twitterrific that ask for features and capabilities that exist in other mobile and desktop software. That’s not surprising, since one of our early decisions with the iPad app was to trim the app down to its bare essentials.

Part of this had to do with schedule constraints. Sixty days was not a lot of time to build a product from scratch.

But a more important reason for paring back the design was to simplify the user interface. A new kind of user is about to be introduced to a computer that they can actually use: less interface is more as far as they’re concerned. We designed our iPad app with our families in mind, not the Twitter power user.

It turns out that our design intuition was pretty good:

The non-tech-savvy users want something simple, to push an icon and get your e-mail and go online. With the iPad, people don’t feel intimidated by it.

Of course, 300,000 geeks like you and me don’t fall into that category. We’re the first ones standing in line at the Apple store, and the first ones to use all this cool new software. And we know all the things that apps “used to do”. And we want all sorts of other bells and whistles. And we’re wrong.

As a developer, you should be very careful about this early feedback for your app. Simplicity is the name of the game in this new world order. You don’t maintain simplicity by adding tons of features.

Two of the most requested features after the 1.0 release of Twitterrific for iPad were Instapaper support and photo uploading. If you think about these things, both have a high cognitive load. To use Instapaper, you need to know that:

The service exists, and that you can signup for an account.

That you can install a bookmark and use it to save pages from your browser.

That these saved pages can be synced to your iPad using another application.

For photo uploading, you have to know how to do one of these things in order to “get a picture”:

Use the camera connection kit to transfer photos, or

Take a screenshot with a non-intuitive gesture (the power and home buttons), or

Tap and hold on a picture in a web page and save it to an album, or

Create events in iPhoto and sync them with iTunes

Ask yourself if you could explain any one of these things to your mother in less than 25 words. I know I can’t and I’m pretty good with this kind of stuff.

Of course, these are both useful features and we added both of them in subsequent releases. In the case of Instapaper, the feature doesn’t even show up in the UI until you go into the Settings app and add your account information. My mom will never see it.

Photo uploading is a simple button on the compose screen that lets you choose a photo from your library. Eventually, our mothers will figure out how to add things to the photo library and use that feature. But they’ll be happiest when a future device let’s us put a “Take Picture Now” button on that screen.

It’s very easy to get caught up in the excitement this new device has generated in the last month and a half, but the real thrill will be in a year’s time when people who’ve never used a computer will be telling you how much they love your app. And there will be a lot more than 300,000 of them…

I’ve always wondered what it would be like to write a book. Now I know. It’s the hardest thing I’ve ever done, but rewarding beyond words.

For those of you asking for PDF or Ebook editions, you can order them now directly from O’Reilly. The printed version will be available in a couple of weeks. The “Look Inside” feature at Amazon.com will give you an idea of what the book covers. I’ve also written an overview of each chapter. (And for those of you who are dying to know, the CHOCKLOCK first appears on page ix.)

If you think you know everything about iPhone development, this book will probably prove you wrong. I learned a lot while writing it, and it’s my sincere hope that you’ll benefit from reading it.